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International Baccalaureate · IB Diploma · Chemistry · HL หัวข้อ 18 3:50 การบรรยายภาษาอังกฤษ · คำบรรยายภาษาอังกฤษ + 中文 ลอยตัวบนภาพ
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Transcript
A reversible reaction 可逆反应 can continue in a closed vessel while measured concentrations stay constant.
可逆反应可以在密闭容器中持续进行，同时测得的浓度保持不变。
Constant composition does not mean particles have stopped reacting.
组成恒定并不意味着粒子停止了反应。
Dynamic equilibrium occurs in a closed system when forward and reverse rates are equal.
动态平衡发生在封闭系统中，此时正反应速率与逆反应速率相等。
Reactant and product concentrations are constant, but they need not be equal.
反应物和生成物的浓度保持恒定，但它们不必相等。
Equilibrium is defined as a state with equal forward and reverse reaction rates.
平衡是指正反应速率与逆反应速率相等的状态。
A reversible reaction is a reaction that can proceed in both directions.
可逆反应是指可以双向进行的反应。
A concentration or pressure change disturbs the balance.
浓度或压强的变化会打破平衡。
The system responds toward a new equilibrium.
系统将向新的平衡状态移动。
Temperature changes can also change the equilibrium constant.
温度变化也会改变平衡常数。
A catalyst changes how quickly equilibrium is reached.
催化剂则改变达到平衡所需的时间。
In the lab: State the balanced equation and whether the forward reaction is exothermic before predicting a temperature effect.
在实验室中，在预测温度效应之前，先写出配平的化学方程式，并说明正反应是放热还是吸热。
Count gas coefficients when considering pressure; pressure has no composition effect when gaseous amounts are equal on both sides.
考虑压强时，需统计气体化学计量数。 当反应前后气态物质的量相等时，压强对平衡组成无影响。
Known: in A double arrow B, equilibrium concentrations are equals 0.20 and equals 0.60 in the same concentration unit.
已知：在 A ⇌ B 中，平衡浓度为 = 0.20 和 = 0.60，单位相同。
For this stated expression, K equals divided by .
对于该表达式，K = / 。
K equals 0.60 divided by 0.20, which is 3.0.
K = 0.60/0.20 = 3.0。
Equal rates do not imply K equals 1.
速率相等并不意味着 K = 1。
Your turn: For A ⇌ B, calculate / when =0.8 and =0.2.
轮到你了。 对于反应 A ⇌ B，当 = 0.8 且 = 0.2 时，计算 / 的值。
Do not use a catalyst to claim a larger equilibrium yield.
不要使用催化剂来声称获得更大的平衡产率。
For heterogeneous equilibria, pure solids are omitted from the usual equilibrium expression.
对于多相平衡，纯固体通常从平衡表达式中省略。
Not true: A catalyst changes the equilibrium constant at a fixed temperature.
不正确。 催化剂会改变固定温度下的平衡常数。
A catalyst speeds the forward and reverse reactions equally, so equilibrium is reached sooner but the equilibrium constant and final composition at a fixed temperature are unchanged.
催化剂同等程度地加快正反应和逆反应，因此更快达到平衡，但在固定温度下，平衡常数和最终组成保持不变。
Dynamic equilibrium occurs in a closed system when forward and reverse rates are equal.
动态平衡在封闭系统中发生，此时正反应速率与逆反应速率相等。
A concentration or pressure change disturbs the balance.
浓度或压强的变化会打破这种平衡。
Watch for: do not use a catalyst to claim a larger equilibrium yield.
请注意：不要使用催化剂来声称能增大平衡产率。
For A in equilibrium with B, the concentration of B is 1.00 and the concentration of A is 0.40, in the same unit.
对于处于平衡状态的A和B，B的浓度为1.00，A的浓度为0.40，单位相同。
Find K for the stated expression of B divided by A.
求表达式B除以A对应的K值。
A catalyst does not change K at a fixed temperature.
在固定温度下，催化剂不会改变K值。
The result is an equilibrium constant of 2.5.
结果是平衡常数为2.5。
The forward rate falls as reactants are used and the reverse rate rises as products form.
正反应速率随反应物消耗而下降，逆反应速率随产物生成而上升。
When the two rates are equal, concentrations stop changing: dynamic equilibrium.
当两个速率相等时，浓度不再改变：这就是动态平衡。
For the equilibrium between A and B, K equals 4 at fixed temperature.
A 等于 B，K 等于 4，温度恒定。
Immediately after adding A, the ratio of B to A is 2.
加入 A 后瞬间，B 与 A 的浓度比值为 2。
Predict the shift and distinguish reaction rates from equilibrium concentrations.
请预测平衡移动方向，并区分反应速率与平衡浓度。
Q is less than K, so a net forward change raises the ratio toward 4.
Q 小于 K，所以反应净向正方向进行，使比值升向 4。
At equilibrium the forward and reverse rates are equal; concentrations need not be equal.
平衡时正、逆反应速率相等，但浓度不一定相等。
Temperature and the stated expression matter.
温度和所给的表达式都很重要。
Retrieve the technical meanings, then vary one input in the original transfer and justify the model condition.
回顾专业术语的含义，然后在原始传递中改变一个输入变量，并论证模型条件的合理性。